A flat panel display comprises a liquid crystal display (LCD), a touch screen (TP), a plasma display panel (PDP) and an organic light-emitting device (OLED). The liquid crystal display draws the most attention in the field of flat panel displays, due to the characteristics of bright image based on superior resolution, low energy consumption as well as thinner display image provided by it. The liquid crystal display is used in movable devices including mobile telephones, and notebook PC, and televisions.
During the process for producing a flat panel display, the use of a glass substrate is demanded. Due to the limitation in the process of the glass substrate, the produced glass substrate is thicker. In order to further reduce the weight of the display devices, more and more manufacturers utilize a process for thinning the glass substrate, and as a result, the etching of the glass substrate became an important issue.
The commonly used thinning process comprises 2 processes, that is a physical process and a chemical etching process. The physical process performs polishing and grinding by using a polishing powder, however, this process is characterized in longer thinning time, un-controllable precision and lower non-defective ratio. The chemical etching process makes use of an etching solution, and this process is characterized in shorter thinning time, lower invest for the apparatus, higher non-defective ratio, and additionally, the thinning liquid has a simple composition and lower cost. Thus, the chemical etching process gradually becomes a main technology process for thinning a glass substrate.
The etching solutions in the prior art have a faster etching rate for the substrate and the etching amount thereof is not easy to be controlled, and thus, the thickness of the substrate cannot be well controlled. Some of the etching solutions cannot effectively dissolve silicates. Some of the etching solutions will produce stronger electro-ionization to produce too much hydrofluoric acid, and thus, the etching rate is not easy to be controlled. Some of the etching solutions produce a great deal of bubbles, which reduces the etching rate.
Therefore, it is demanded to provide an etching solution and a process for etching a glass substrate, which dissolves the precipitated impurities attached to the surface of the substrate after substrate thinning so as to remove effectively the impurities on the surface of the substrate, improves the qualified ratio and non-defective ratio of the products, and at the same time, provides the effective insurance for controlling the thickness of the substrate.